Has anyone tried this? I'm kind of curious as to what the theaters use as their reference level. Sometimes it gets loud in there and sometimes I can't hear it very well. BTW, what's the standard ref level again, 105dB?

You will probably never get a definite answer about the levels: it varies with the room, and within the same room, with the movie, and with the same movie in the same room, it varies with the showing! I had to go out and ask them to turn the volume up on Gladiator the second time I watched it: It was definitly much lower than the first time.
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Holadem

I did bring my radio shack SPL meter into my local theater and I measured normal dialog to be on average at 85db's and
during heavy action scenes I was getting it spiking to 115db's. I was seating in the center about 1/2 way up. The
readings kind of surprised me because the sound seemed normal to me for a theater, not overly loud.

While I didn't bring the meter with me (I'll know I'm hopeless at that point ), I did close my eyes and try to pay attention to the actual sound level when I went to see Jurassic Park 3 some time ago. Sure enough, it was much louder than I run my system at home (10db under reference), but, like David said, didn't seem all that loud, implying that my system is straining somewhat, while the theater's sytems likely wasn't.
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